57 



(i) Ultimate segments not dimidiate 

 (i.e. halved or appearing as if one 

 half had been cut off), but having 

 two or more distinctly opposite 

 rows of sori. 



3. A. peruvianum. 



(ii) Ultimate segments dimidiate. 



(1) Stems naked and polished. Ulti- 



mate pinnules i|-2 inches 

 Ing. Texture thin. 



4. A. trapezi forme. 



(2) Stems hairy, rough. Ultimate 



pinnules J-j inch long. 

 Texture almost leathery. 



5. A. formosum. 



(c) Oligosorous Group. Frond once or 

 more pinnate. Sori more or less continuous on 

 either side of the leaflet. 



6. A. macrophyllum. 



(d) Capillus-Veneris Group. Frond at 

 least bipinnate ; segments fan-shaped with the 

 stalk near the centre ; sori oblong or obversely 

 kidney-shaped. 



